How are characters in Wieland suffer with actions whose consequences are in excess of what they intended

Much of your question can be explored within the theme of madness. Often insanity makes them misjudge the limits of what they intended. The Wieland family has three generations of insanity. Clara and Theodore's maternal grandfather heard voices commanding him to throw himself off a cliff. Their father was obsessed with the writings of a strange Protestant sect and let that obsession take over his mind. Wieland either allowed Carwin's voices to lead him to murder his family in the name of God or imagined the voices within his head. Clara is a victim of hysteria and irrationality; she considers suicide multiple times, cannot distinguish between dreams and reality, goes mad after her brother commits suicide, and uses supernatural explanations for everything she does not understand. This insanity is handed down from generation to generation. The Wieland children think they have escaped it but are fated to play out the same scenes as their forebearers.